Stereochemistry and Mechanistic Insight in the [2k+2i+2i] Annulations of Ketenes and Imines

Yang, Zhanhui; He, Wei; Cheng, Baoxiang; Xu, Jiaxi

doi:10.1021/acs.joc.6b00279

Cited by 18 publications

(8 citation statements)

References 56 publications

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“…Benzyl (3-diazo-2-oxopropyl)carbamate ( 31 ), quantitative yield, transparent amorphous solid. 1 H NMR (400 MHz, CDCl 3 ) δ (ppm) = 7.42–7.31 (m, 5H), 5.46 (s, 1H), 5.39 (s, 1H), 5.13 (s, 2H), 3.99 (s, 1H); as reported [ 52 ].…”

Section: Methodssupporting

confidence: 58%

Synthesis of 3-Amino-4-substituted Monocyclic ß-Lactams—Important Structural Motifs in Medicinal Chemistry

Grabrijan

Strašek

Gobec

2021

IJMS

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Monocyclic ß-lactams (azetidin-2-ones) exhibit a wide range of biological activities, the most important of which are antibacterial, anticancer, and cholesterol absorption inhibitory activities. The synthesis of decorated monocyclic ß-lactams is challenging because their ring is highly constrained and consequently reactive, which is also an important determinant of their biological activity. We present the optimized synthesis of orthogonally protected 3-amino-4-substituted monocyclic ß-lactams. Among several possible synthetic approaches, Staudinger cycloaddition proved to be the most promising method for initial ring formation, yielding monocyclic ß-lactams with different substituents at the C-4 position, a phthalimido-protected 3-amino group, and a (dimethoxy)benzyl protected ring nitrogen. Challenging deprotection methods were then investigated. Oxidative cleavage with cerium ammonium nitrate and ammonia-free Birch reduction was found to be most effective for selective removal of ring nitrogen protection. Hydrazine hydrate was used for deprotection of the phthalimido group, and the procedure had to be modified by the addition of HCl in the case of aromatic substituents at the C-4 position. The presented methods and the synthesized 3-amino-4-substituted monocyclic ß-lactam derivatives are an important step toward new ß-lactams with potential pharmacological activities.

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Section: Methodssupporting

confidence: 58%

Synthesis of 3-Amino-4-substituted Monocyclic ß-Lactams—Important Structural Motifs in Medicinal Chemistry

Grabrijan

Strašek

Gobec

2021

IJMS

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“…The traditional method for the synthesis of dihydroisoquinoline is stemmed from 1,2,3,4-tetrahydroisoquinoline (THIQ), which is dehydrogenated under the induction of hydrogen acceptors, 3 or oxidizing agents are used under an argon atmosphere. 4 The former method has the advantages of simple operation without deoxygenation and the use of air as the oxidant, 5 which is cheap and easy to obtain. However, there are challenges in the photocatalytic oxidation of such compounds in aqueous media.…”

Section: Introductionmentioning

confidence: 99%

“…DHIQ is a representative of a class of N‐heterocyclic small molecule compounds widely distributed in nature and synthetic materials. The traditional method for the synthesis of dihydroisoquinoline is stemmed from 1,2,3,4‐tetrahydroisoquinoline (THIQ), which is dehydrogenated under the induction of hydrogen acceptors, 3 or oxidizing agents are used under an argon atmosphere 4 . The former method has the advantages of simple operation without deoxygenation and the use of air as the oxidant, 5 which is cheap and easy to obtain.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin triphenylamine–perylene diimide polymer with D–A structure for photocatalytic oxidation of N‐heterocycles using ambient air

Zhang

et al. 2022

EcoMat

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An ultrathin porous triphenylamine–perylene diimide (PDI) polymer photocatalyst with photooxidative ability was prepared. Triphenylamine–PDI oxidizes 1,2,3,4‐tetrahydroisoquinoline to 3,4‐dihydroisoquinoline with a yield of 84% and selectivity of 92% under the following conditions: room temperature, ambient air, aqueous solution and 420 nm irradiation. The yield was 62% higher than that of mesoporous g‐C3N4 and 72% higher than that of self‐assembled PDI. The high yield and enhanced catalytic activity of the triphenylamine–PDI were attributed to the introduction of the electron‐donating triphenylamine motif into PDI, thereby forming a donor–acceptor structure, which greatly promotes the separation of photogenerated charges. In addition, the triphenylamine–PDI with high crystallinity of was conducive to fast charge transport. Triphenylamine–PDI was also applicable to other N‐heterocyclic substrates. Moreover, using aqueous media and air as oxidant are consistent with green chemistry, and the photocatalyst can be recycled after the reaction.

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“…Imines are one of the most versatile functional groups in synthesis. Numerous studies have focused on their preparation [ 1 , 2 , 3 , 4 , 5 ], chemical structure and tautomeric or transimination equilibrium [ 6 , 7 , 8 ], and use as a precursor for the construction of more complex structures [ 9 , 10 , 11 , 12 ]. Due to their versatility, they play an important role in medicinal chemistry, serving as urease and protease inhibitors [ 13 ] as well as antimalarial, antibacterial, and antifungal agents [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles

et al. 2021

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An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cyclization of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H activation. In a single-step approach, a variety of 2-substituted indoles were also generated via a Hg(I)/Pd(II)-catalyzed, one-pot, two-step process, starting from anilines and terminal acetylenes. The arylacetylenes proved to be more effective than the alkyl derivatives.

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Stereochemistry and Mechanistic Insight in the [2^k+2ⁱ+2ⁱ] Annulations of Ketenes and Imines

Cited by 18 publications

References 56 publications

Synthesis of 3-Amino-4-substituted Monocyclic ß-Lactams—Important Structural Motifs in Medicinal Chemistry

Synthesis of 3-Amino-4-substituted Monocyclic ß-Lactams—Important Structural Motifs in Medicinal Chemistry

Ultrathin triphenylamine–perylene diimide polymer with D–A structure for photocatalytic oxidation of N‐heterocycles using ambient air

Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles

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